@Sayali Desai - good questions, and these answers apply to all of our exams:
1. If you get disconnected, you simply reload the webpage that the exam is on. If you lose that page, you log back in to examslocal.com and re-launch the exam from there.
2. If you are facing lag during the practice exam, then you will likely get the same lag during the real exam. The lag is due to your internet connection either not being fast enough or consistent enough. VNC is a stream of images, and anytime your internet is slow or drops a connection to the VNC server, it creates the appearance of lag (even though the VM is running fine behind the scenes). If this happens, please let the exam proctor know. He/she will give you more time to complete the exam.
TIP: If your internet is affecting your ability to accomplish anything on the exam, or if you are experiencing any type of technical issues with your HDP cluster or environment, let the proctor know. If it's a cluster issue, they will reach out to our technical support team to help try to fix the issue. If any problems can not be resolved in a timely fashion, you can simply stop the exam and reschedule it again.